The atrial appendage is a feature of all human hearts. The upper chambers of the heart, the atria, have this appendage attached to each of them. The physiologic function of such appendages is not completely understood, but they do act as a filling reservoir during the normal pumping of the heart. The appendages typically protrude from the atria and cover an external portion of the atria. Atrial appendages differ substantially from one to another in size, shape and specific location with respect to the atria. For example, one atrial appendage may be configured as a tapered protrusion while another atrial appendage may be configured as axe-entrant, sock-like hole. The inner surface of an appendage is conventionally trabeculated with cords of muscular cardiac tissue traversing its surface with one or more lobes.
The atrial appendages are inert while blood is being pumped through them during normal heart function. In other words, the appendages don't have a noticeable effect on blood pumped through them during normal heart function. However, in cases of atrial fibrillation, when the atria go into arrhythmia, blood may pool and thrombose inside of the appendages. Among other things, this can pose a stroke risk when it occurs in the left appendage since the thrombus may be pumped out of the heart and into the cranial circulation. Such can also lead to ischemic damage of other organs of the body.
Historically, atrial appendages have sometimes been modified surgically to reduce the risk imposed by atrial fibrillation. In more recent years, devices which may be delivered percutaneously into the left atrial appendage have been introduced. The basic function of these devices is to exclude the volume within the appendage with an implant which then allows blood within the appendage to safely thrombose and then to be gradually incorporated into cardiac tissue. This can leave a smooth, endothelialized surface where the appendage used to be.
In comparison to surgical procedures, devices implanted percutaneously are clearly a less invasive means for addressing the problems associated with the left atrial appendage. However, due to the wide variability of the size of the ostium and the volume of an atrial appendage, implant devices that are currently used typically include structure that cannot meet such variability, resulting in inadequate devices for many left atrial appendages. Further, such implant devices are substantially limited by the orientation by which they can successfully be deployed. Thus, successful placement and deployment of such devices becomes limited.
As such, it would be advantageous to provide percutaneous systems, methods and devices that, among other things, address one or more issues such as implant orientation and the variability in sizes of the left atrial appendage in order to provide high success in left atrial appendage modification.